China's Zai Lab falls, despite positive Phase III PRIME Study of Zejula

Shares of Chinese biotech Zai Lab Limited (HKEX: 9688) closed down 7% at HK$562 yesterday, even though the company announced that the Phase III PRIME study of Zejula (niraparib) as maintenance therapy met its primary endpoint.

Zejula demonstrated a statistically-significant and clinically-meaningful progression-free survival (PFS) benefit with a tolerable safety profile in Chinese patients with newly diagnosed advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer (collectively termed as ovarian cancer) following a response to platinum-based chemotherapy, regardless of biomarker status.

“I believe the data of the PRIME study will have a significant impact on the clinical practice in the first-line treatment of ovarian cancer in China and beyond, as the individualized starting dose regimen has demonstrated a clear clinical benefit with an improved safety profile,” said Dr Lingying Wu, director of the Department of Gynecologic Oncology, National Cancer Center / National Clinical Research Center for Cancer / Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, adding: “In addition, the PRIME study is the only study conducted in China that has demonstrated that a PARP inhibitor significantly improved PFS when given as monotherapy maintenance therapy in all Chinese patients with newly diagnosed ovarian cancer, regardless of biomarker status.”